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Soil Stabilization by Chemical Agent
Abstract
Soil treatment is commonly resorted in order to improve the strength, stiffness properties of road foundations, and reduce the swelling potential of expansive soils. In Jordan, considerable amount of construction activity is carried out at relatively shallow depths where soil is likely to be unsaturated and subjected to low stresses level. Road damage is frequently observed when it is founded on weak sub-grade in Karak. Therefore, chemical stabilization of the base course, sub base course and sub-grade is essential. The soil will be treated by using sodium silicate and lime with different percentages. An experimental program was designed to study the behavior of soil as the percent of additive agent changes. The results showed that; the geotechnical properties have been improved when soil is treated by mixing lime and sodium silicate. The initial consumption of lime is of 4 and 2 % for sodium silicate. The reaction time is a significant parameter where strength improves as time increases.
... Chemical stabilization is a soil improvement method in which, chemically active compounds are used to improve the soil properties (Maaitah 2012). Cement, lime, and fly ash are examples of such compounds that can be used (Ardah et al. 2017). ...
... However, lime as a chemical stabilization compound, is more traditional and is the oldest known (Qubain et al. 2000). It has since been used in many cases during road or highway construction projects to improve the soil stiffness, strength, bearing capacity, durability, and settlement (Qubain et al. 2000;Maaitah 2012;Rout et al. 2012;Ahmed et al. 2020). Moreover, the use of lime in comparison to Portland cement is beneficial for carbon emission reduction and sustainability. ...
... Portland cement is responsible for 5-8% of global man-made CO 2 emissions (Filippo et al. 2019;Gartner and Hirao 2015). The improved soil properties are attained through three mechanisms: cementation, hydration, and flocculation (Qubain et al. 2000;Maaitah 2012). Cementation is a lime and soil reaction that forms various cementitious gels; hydration is a reaction between lime and water; and flocculation is a process in which the clay particles are rearranged to become very closely packed together. ...
Column experiments were conducted in this study on treated and untreated sensitive marine clay to understand the evolution of the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes that occur in the treated and untreated marine clay by monitoring the soil samples over a period of 28 days. Three columns in which sensors were placed within the compacted soil samples and a dial gauge at the top were set-up to allow monitoring of the evolution of the THMC processes. Nine other columns were also prepared and set-up from which samples for extensive testing were obtained after 1, 3, 7, and 28 days. The mechanical properties of the soil increased significantly due to the lime treatment in which pozzolanic reactions occurred. The study showed that the improved mechanical properties were coupled with the chemical reactions—monitored through electrical conductivity, temperature evolution within the column and suction which developed with time. Properties such as the hydraulic conductivity were equally affected, to which pore refinement as a result of lime hydration, was attributed. The coupled THMC behavior was noted to have been highly dependent on the hydration of lime. To understand the behavior of treated pavement subgrades, the effects of the coupled process presented in this study need to be understood to further design cost effectively and have pavements of long service lives.
... Over past decades, one of extensively used techniques for soil stabilization is using customary cementitous additives such as cement, lime, and fly ash [1][2][3][4][5]. Among all, cement is often used as a principle additive to enhance mechanical properties of soil such as strength and stiffness within a curing time [6][7][8][9]. One of the most dominant types of soil in tropical regions is residual soil [10]. ...
... One of the most dominant types of soil in tropical regions is residual soil [10]. Many researchers reported that addition of 6-10% cement to residual soil with plasticity indexes in a range of 10-20% has been recommended to achieve the maximum possible strength for base construction [7,[11][12][13]. Improvement in properties of cement treated residual soil has been mainly attributed to soil-cement reactions [3,14], which produce primary and secondary cementitious materials in the soil-cement matrix [12,15,16]. ...
... The results of unconfined compression test of specimens cured at 7, 14, and 28 days are presented in Fig. 7(a)-(d), respectively. As can be seen, the compressive strength was improved with the increase of cement content and curing time which is in agreement with the previous studies [3,7,9,20,43,48,49]. Fig. 7(a) depicts the effect of 0.2, 0.4, 0.8, and 1% nanosilica (15 nm) on the compressive strength of soil treated with 6% cement (by weight of soil) in the course of time. ...
... The selection of the mentioned alternative stabilisers was made in accordance with the results of previous research, in which it was established that the addition of these materials could improve certain properties of the soil. Thus, for example, an increase in soil bearing capacity was achieved by adding magnesiumbased materials [41,42], or sodium silicate [43]. Studies have shown that chloride-based electrolytes can be effectively used instead of lime in soil stabilisation owing to their better solubility, easier mixing with the soil, and provision of the necessary cations for the cation exchange process [29]. ...
... In the available literature, the content percentage of magnesium-based additives and sodium silicate does not exceed 10% [27,28,[41][42][43], whereas the content of these additives in combination with other stabilisers is often lower than 3% [33,34,44]. Therefore, for the purposes of this research, as was the case with the samples with added lime, mixtures with the addition of 3%, 5%, and 7% of magnesium carbonate were tested, and the same percentages were chosen for the mixtures with sodium silicate. ...
The unconfined compressive strength and shear strength represent the basic mechanical properties of clayey soil. If the soil in its natural state does not have sufficiently good mechanical properties, in engineering practice, it can be improved by chemical stabilisation of the soil. The stabilisation procedure involves adding reagent(s) to the soil with the aim of permanent improvement in the mechanical properties of the soil. In this study, the individual effects of seven different chemical stabilisers (traditional and alternative) on the mechanical properties of clayey soil were analysed. In the first stage of the research, comprehensive analyses were conducted on the effect of each of the selected stabilisers on the compressive strength of the soil. Each of the selected stabilisers was considered with three different content percentages in the soil mixture, with the aim of determining the optimal stabiliser content. Unconfined compressive tests were conducted to determine the unconfined compressive strength (UCS) of the soil. In the second stage of the research, extensive analyses of the effects of each of the selected stabilisers alone on the improvement in soil shear strength parameters (cohesion and internal friction angle), were carried out with the optimal content of each of the stabilisers. The shear strength parameters were determined by direct shear tests. Both stages of the research were conducted at three different time intervals after the chemical stabilisation (3, 14, and 28 days) in order to determine the long-term efficiency of the chemical treatment of clayey soil. Based on detailed comparative analyses, it was determined that all the selected stabilisers contributed to a lesser or greater extent to a significant improvement in the analysed mechanical properties of clayey soil. A statistical analysis of the obtained results was also conducted using the method of analysis of variance (ANOVA), on the basis of which the individual effect of each selected stabiliser on improving the mechanical properties of clayey soil was validated and quantified.
... A lot of researchers have based their research on this lime content for modification of soil properties [3,[18][19][20]. Some of the researchers have also referred to this lime content as Lime Modification Optimum (LMO) [21][22][23]. However, it has been found that ICL content modifies the soil properties but was found to contribute only nominally to the strength development of the stabilized soil through pozzolanic reactions because enough lime is not available for reactions to proceed with time. ...
... This prevents any external atmospheric variation in the moisture content affecting the specimens as well as prevents loss of moisture from the specimens. Some investigators [11,21,23,60] adopted this air curing technique in their investigations. Others adopted a technique wherein the prepared specimens were moisture cured to ensure that the stabilized specimens had sufficient moisture content available for the pozzolanic reactions to proceed. ...
Soil stabilization is a common engineering technique used to improve the physical properties of weak soil in order to achieve the desired engineering requirements. Among the various chemical stabilization techniques adopted for expansive soils, lime stabilization is the most widely adopted for controlling the swell-shrink properties of expansive soils. This study reviews the major research works carried out in the application of lime stabilization and attempts to understand various parameters that influence the effectiveness of lime stabilization. The different parameters that have been discussed include Soil Type and Mineralogy, Type, Quantity and Quality of Lime, Curing Period, Type of Curing, Curing Temperature, Moulding / Placement Water Content, Pulverization Quality, Strain Rate, pH, Organic Content, Sulphates and Extreme Conditions.
... They showed that adding 5% rice husk fly ash with 4% lime is most effective in increasing the compressive strength of the soil [13]. Maaitah (2012) showed that the strength of soil mixed with 4% hydrated lime and 2% sodium silicate was increased significantly [14]. Al Adili et al. (2012) showed that papyrus fiber can be considered an appropriate material for reinforcement of soils [15]. ...
... They showed that adding 5% rice husk fly ash with 4% lime is most effective in increasing the compressive strength of the soil [13]. Maaitah (2012) showed that the strength of soil mixed with 4% hydrated lime and 2% sodium silicate was increased significantly [14]. Al Adili et al. (2012) showed that papyrus fiber can be considered an appropriate material for reinforcement of soils [15]. ...
Production of sewage sludge have raised increasing concerns due to negative environmental effect. Sewage Sludge Ash (SSA) is used as a new type of additive for clay. Laboratory tests were performed on clay samples to study the mechanism of sewage sludge ash (SSA) and Hydrated Lime (HL) soil stabilization. Different SSA contents (0, 5, 10, 15%) and hydrated lime (0, 1, 3 and 5%) were added to the soil samples. 288 samples were prepared, and unconfined compressive strength tests were carried out. The samples were tested under optimum water content and also saturated conditions with three replications. The results of the coefficient of softening indicated that by adding SSA and hydrated lime to clay soil simultaneously, the stabilized clay soils can be applied in the moist and saturated condition. According to the results, the samples of SSA contents 0% with hydrated lime 5% and SSA contents 10% with hydrated lime 5% can be placed in the vicinity of moisture.
... This shows that the Helmut chemical plays a role in reducing the swelling potential of the Balikpapan soil because the calcium silicate content, which can fill the voids in the soil particles, increases the strength and hardness of the soil. In addition, the water involved in the reaction between Ceta(OH)2 and Na2SiO3, which is also the constituent of Helmut, will act as a restraint on the structure of the silicate, which also has an impact on reducing its swelling [8]. ...
... Lateritic soil (LS), characterized by high plasticity, compressibility, and sensitivity to moisture variations, presents notable challenges in road construction. Seasonal cycles of swelling and shrinking exacerbate these issues, affecting the soil's hydro-mechanical behavior and undermining pavement structural integrity [16][17][18]. While lateritic soil is widely used, addressing its variability and ensuring compliance with construction standards are critical for reliable road construction materials [19][20][21]. ...
This study investigates the stabilization of lateritic soil through partial replacement of cement with flue gas desulfurization (FGD) gypsum, aiming to enhance its engineering properties for pavement subgrade applications. Lateritic soils are known for their high plasticity and low strength, which limit their utility in infrastructure. To address these challenges, soil specimens were treated with varying cement contents (3%, 6%, 9%) and FGD gypsum additions (1%–6%). Laboratory tests were conducted to evaluate plasticity, compaction, permeability, unconfined compressive strength (UCS), California Bearing Ratio (CBR), and fatigue behaviour. The optimal mix 6% cement with 3% FGD gypsum demonstrated significant improvements: UCS increased by over 110% after 28 days, permeability reduced by 26%, and soaked CBR improved by 56% compared to untreated soil. Additionally, fatigue life showed remarkable enhancement under cyclic loading, indicating increased durability for high-traffic applications. To support predictive insights, machine learning models including Decision Tree, Random Forest, and Multi-Layer Perceptron (MLP) were trained on 168 data samples. The MLP and Random Forest models achieved high prediction accuracy (R² ≈ 0.98), effectively capturing the non-linear interactions between mix proportions and UCS. SHAP (SHapley Additive exPlanations) analysis identified curing duration as the most influential factor affecting strength development. This integrated experimental–computational approach not only validates the feasibility of using FGD gypsum in sustainable soil stabilization but also demonstrates the effectiveness of machine learning in predicting key geotechnical parameters, reducing reliance on extensive laboratory testing and promoting data-driven pavement design.
... Soil replacement is used to remove clayey soil and replace it with high-quality, less moisture-susceptible soil [12]. Chemical modification involves adding substances to the soil to alter its chemical properties, promote ion exchanges, fill voids, and make the soil less attractive to water [13,[15][16][17][18]. Regardless of the chemicals employed for soil stabilization, the treated soil typically remains unable to support vegetation due to alterations in chemical and biological conditions as well as limited water availability. ...
Superabsorbent polymers (SAPs) have been used in agriculture as a soil conditioner to regulate moisture in soils to promote plant growth. Its impact on hydraulic properties has been studied at different scales and with different focuses. The water retention capacity of SAPs could potentially be useful for various engineering applications, particularly, for clayey soils. This study focuses on assessing one type of SAPs, i.e., sodium polyacrylate, for its potential to mitigate the change of properties due to fluctuation of moisture in the clay soil. Lab tests were conducted to quantify the variation of absorbency of sodium polyacrylate with time. Thereafter, this SAP was added into clayey soil as an additive at a dosage of 0.5%, 1%, or 2% with varying water content, afterwards, the prepared soils were subjected to standard Proctor and direct shear tests. Both tests indicated that sodium polyacrylate is an effective soil conditioner to preserve the engineering properties of clay by mitigating the impact of fluctuating moisture. By adding SAP, the maximum dry unit weight of soil decreases by more than 10%, while the impact of water on dry unit weight of compacted soil becomes less salient, namely, by increasing the moisture content of 2% SAP soil from 15 to 23%, the dry unit weight varies only between 14.7 kN/m³ to 15.0 kN/m³. The direct shear tests indicate less variation of cohesion and friction angles with soil water content increase. Specifically, when the soil moisture content increases from 17 to 25%, the friction angle and cohesion of soil decrease by 86% and 83%, respectively. In contrast, by adding 2% SAP, the friction angle and cohesion only decrease by 21% and 28%, respectively. SEM imaging shows that the added SAP acts as a film, covering the soil particle surface, which weakens the direct impact of water on soil properties. In summary, by adding SAP the soil shear strength becomes much less sensitive to moisture fluctuation, which makes it suitable of various surficial soil improvement for slopes, embankments and roadway subgrade that often experience significant and frequent moisture changes.
... However, in many cases, it is not enough to ensure the strength and stiffness properties and reduce the swelling potential of expansive soils (Firoozi et al. 2017). Thus, chemical stabilization is necessary for these situations (Maaitah 2012). Binders are materials that, when in contact with water or with pozzolanic minerals, react and form cementitious composites. ...
... The processes based on changing the engineering properties of soils by chemical reactions with various additives (FA, L, etc.) are chemical stabilization [10]. Chemical stabilization is used for the stabilization of expansive soils. ...
Soils may not always be suitable to fulfill their intended function. Soil improvement can be achieved by mechanical or chemical methods, especially in transportation facilities. L and FA additives are frequently used as chemical improvement additives. In this study, two natural clay samples with extreme and very high plasticity were improved by using L and FA admixtures, and their properties under static and repeated loads were investigated by ML methods. Two soil samples from two different sites were analyzed. In this study, eight datasets were used. There are 14 inputs, including specific gravity (Gs), void ratio (eo), sieve analysis (+No.4, −No.200), clay size, LL, plastic limit (PL), plasticity index (PI), linear shrinkage (Ls), shrinkage limit (SL), cure day, agent, clay type, and agent percentage. The outputs are index and swelling properties (compressive, percent), compressive strengths, modulus of elasticity, and compressibility properties in soaked and non-soaked conditions. Prediction is attempted with different ML (ML) techniques. ML techniques used for regression (such as Decision Tree Regression (DTR) and K-nearest neighbors (KNN)). SHapley Additive Explanations (SHAP), the impact of inputs on outputs were observed, and it was generally found that PL and LL had the highest impact on outputs. Different performance metrics are used for evaluation. The results showed that these ML techniques can predict the static and cyclic properties of extremely high plasticity clays with high performance (R² > 0.99). These results highlight the general applicability of the used ML models on different datasets containing soil properties.
... Reactions between the stabiliser and the clay occur through two distinct processes: the process of rapid ion exchange reactions, known as soil modification, and the process of slower pozzolanic reactions, known as soil stabilisation or hardening (Maaitah, 2012). ...
... The choice of enzyme-induced carbonate precipitation led to improvements in crust thickness (142%), penetration resistance (800%), and calcium carbonate content (1.4%), which promoted the better erosion resistance of the coarse-grained soil [13]. Maaitah [14] stabilized an HCC soil by combining sodium silicate with lime and improved the CBR of the soil by 153%. ...
Acacia gum (AG), a polysaccharide biopolymer, has been adopted to improve the strength of three cohesive soils by subjecting them to diverse environmental aging conditions. Being a polysaccharide and a potentially sustainable construction material, the AG yielded flexible film-like threads after 48 h upon hydration, and its pH value of 4.9 varied marginally with the aging of the stabilized soils. The soil samples for the geotechnical evaluation were subjected to wet mixing and were tested under their Optimum Moisture Content (OMC), as determined by the light compaction method. The addition of AG modified the consistency indices of the soils due to the presence of hydroxyl groups in AG, which also led to a rise in OMC and reduction in Maximum Dry Unit weight (MDU). The Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) were determined under thermal curing at 333 K as well as on the same day of sample preparation. The least performing condition of the soil’s CBR was evaluated under submerged conditions after allowing the AG-stabilized specimens to air-cure for a period of 1 week. The UCS specimens tested after 7 days were subjected to the initial 7 days of thermal curing at 333 K. A dosage of 1.5% of AG yielded the UCS of 2530 kN/m² and CBR of 98.3%, respectively, for the low compressible clay (LCC) after subjecting the sample to 333 K temperature for 1 week. The viscosity of the AG was found to be 214.7 cP at 2% dosage. Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and average particle size determination revealed the filling of pores by AG gel solution, adsorption, and hydrogen bonding, which led to improvements in macroproperties.
... Accepting this state and noting the necessity for rational ground improvement, researchers are devoted to using nonconventional additives in problematic soils [20,21,22,23,24,25,26,27]. Their main attraction is industrial byproducts, with several research works conducted in recent years to justify their use, although availability is a major issue [28,29,30]. ...
The expansive soil swells significantly in the presence of moisture, which often leads to the failure of superstructures. Conventional stabilization techniques are applied in many instances, although environmental issues are of significant concern for such stabilization. Keeping this in mind, an attempt is made to apply a new approach for stabilizing different types of expansive soils, treated with a nonconventional binder geopolymer that utilizes fly ash as the main ingredient. A series of laboratory experiments are run to determine the engineering properties of treated soils with varying percentages of geopolymer from 0% to 30%. The experimental investigation involved tests such as unconfined compressive strength, compaction, Atterberg limits, and swelling pressure. Significant strength development occurs with increasing percentages of geopolymer, and their swelling pressures decrease considerably. Additionally, a series of California Bearing Ratio (CBR) tests were undertaken to assess the suitability for road construction. The optimum dosage of the stabilizing agent is found to be 20%, as justified by studies in the literature. Furthermore, scanning electronic microscope (SEM) images of the treated samples revealed microstructural changes in the soil matrix, which strongly correlate with the improvement of strength and swelling behavior. Hence, based on our experimental results, 20% geopolymer content is sufficient for enhancing the engineering properties of expansive soils, and the treated soils can directly be used as subgrade or sub-base material.
... In the past decades, chemical soil stabilization has been widely used in pavement structure. This technique combines the use of local soil with cement to provide a strong material, which, when used in layers of the pavement, can support traffic loads [1][2][3][4][5][6]. ...
This work deals with the flexural performance of a soil-cement for pavement reinforced by polypropylene and steel fibers, and the main purpose is to evaluate the effect of different curing times. In this sense, three different curing times were employed to investigate the influence of fibers on the material’s behavior at varying levels of strength and stiffness as the matrix became increasingly rigid. An experimental program was developed to analyze the effects of incorporating different fibers in a cemented matrix for pavement applications. Polypropylene and steel fibers were used at 0.5/1.0/1.5% fractions by volume for three different curing times (3/7/28 days) to assess the fiber effect in the cemented soil (CS) matrices throughout time. An evaluation of the material performance was carried out using the 4-Point Flexural Test. The results show that steel fibers with 1.0% content improved by approximately 20% in terms of initial strength and peak strength at small deflections without interfering the flexural static modulus of the material. The polypropylene fiber mixtures had better performance in terms of ductility index reaching values varying from 50 to 120, an increase of approximately 40% in residual strength, and improved cracking control at large deflections. The current study shows that fibers significantly affect the mechanical performance of CSF. Thus, the overall performance presented in this study is useful for selecting the most suitable fiber type corresponding to the different mechanisms as a function of curing time.
... Chemical admixture and cement are among the most commonly used methods for soil stabilization. However, their environmental impact and effects on soil health are significant concerns [5]. While chemical and cement stabilization improve soil strength and physical properties, they can also have adverse effects on the soil ecosystem and environment [6]. ...
Biopolymers are emerging as sustainable and eco-friendly soil stabilizers, but there is a lack of studies investigating their long-term effectiveness. Municipal Solid Waste Fines (MSWF), the portion of MSW that passes through a 4.75 mm sieve, were treated with two biopolymers, Xanthan Gum and Agar Gum, and cured at a constant moisture level and room temperature for 7–180 days. Triaxial tests were conducted to determine shear strength parameters at different curing periods and biopolymer concentrations. Results showed that the shear strength of the treated MSWF increased more than 2.5 times when treated with 1.5 % of Xanthan Gum and Agar Gum. The shear strength increased from 85.2 kPa to 307.1 kPa and 322.2 kPa for Xanthan Gum and Agar Gum, respectively. Both biopolymers also improved the angle of internal friction and cohesion of the MSWF with long-term curing. Xanthan Gum exhibited a slower rate of strength gain over a period of up to three months, while Agar Gum-treated MSWF gained the ultimate strength more quickly. Agar Gum showed better strength properties due to its better gel stiffness, and a microstructure study demonstrated that these biopolymers consistently tend to fill pores when used over an extended period. The long-term stability of biopolymer-treated MSWF reflects a green approach, emphasizing the potential for circularity, sustainability, and reduced emissions.
... Harichane et al. [12] found that the shear strength of stabilized soils increases with increasing confining pressure. The variation of additive content in soil stabilization has a significant effect on strength gain [30]. In another study, the shear strength of both stabilized clayey soils (CL and CH) increases with increasing lime and NP content [11]. ...
Stabilization of cohesive soils has been practiced for some time by mixing additives, such as cement, lime, and fly ash, into the soil to increase its mechanical strength. However, there is a lack of investigation on the use of natural pozzolana (NP) alone or combined with lime for soil stabilization applications. This work is a part of a research project focused on the evaluation of the effects of adding natural pozzolana as an additive to improve the lime treatment results of local clayey soils. The main purpose of this paper is to present the results of using lime, natural pozzolana, and their combination on shear strength, shear parameters, and failure mode variations of the local clayey soil, classified as fat clay (CH). CH, selected from Tlemcen city in Algeria, is known for its high plasticity and importance in cohesion and compressibility. To achieve this goal, several physicomechanical tests (pH, compaction, undrained unconsolidated triaxial compression test) and microstructural analysis, scanning electron microscope (SEM) have been carried out for the different studied combinations. Natural pozzolana and lime were added to the studied soils at ranges of 0–20% and 0–6%, respectively. The treated samples were cured for 1, 7, and 28 days. The results indicated that the studied properties of clay soil can be considerably improved when treated with lime. The combination of lime and natural pozzolana appears to produce higher shear strength parameters, than when lime or natural pozzolana is used alone. Adding natural pozzolana to clay soil treated with lime produces an additional chemical reaction, especially in the long term, resulting in better flocculation and additional formation of cementing materials. Therefore, the deviatoric stress of the treated soil, with 6% lime and 20% NP, increased up to 200% within 28 days of curing. The treated soil became more brittle, with a significant increase in shear strength, cohesion, and a higher friction angle.
... The high-calcium and low-calcium fly ashes affecting on highly expansive soil was studied by Mir and Sridharan (Mir & Sridharan, 2013). Maaitah (2012), stated that the mixing sodium silicate and lime could be improved the engineering properties of treated soil. Prabakar et al. (2004) studied the effectiveness of fly ash on the engineering properties against various types of soils. ...
... Chemical admixture and cement are among the most commonly used methods for soil stabilization. However, their environmental impact and effects on soil health are significant concerns [5]. While chemical and cement stabilization improve soil strength and physical properties, they can also have adverse effects on the soil ecosystem and environment [6]. ...
... Electrical treatment can be performed either by dewatering or hardening by electro-osmosis (Afrin, 2017;Jeyapalan et al., 1981), whereas thermal stabilization consists of heat treatment and stabilization by cooling (Jeyapalan et al., 1981). However, chemical stabilization has been the most popular choice (Maaitah, 2012) in the current context since it enables the full use of in-situ soils, thus offering enormous cost benefits and minimizing the long haul distances. It also has the ability to control the setting and curing times. ...
Geopolymer based soil stabilization is an emerging research field as shown by recent research studies which indicate strong potential of their wide use for sustainable ground treatment. This paper comprehensively reviews the literature on expansive soil stabilization using alkali activated binders, focusing on the stabilization mechanism and geotechnical characteristics of treated soil inclusive of mechanical strength and durability characteristics. The stabilization mechanism is governed by the cation exchange process and the geopolymer/hydration products formation. The reported highest unconfined compressive strength (UCS) and California bearing ratio (CBR) of the geopolymer treated expansive soil cured at room temperature are 15 MPa and 81%, respectively and these values satisfy the strength criteria of most of the standards used for road base materials. The findings of the review revealed that incorporation of precursors in the range of 15-20%, alkaline molarities between 5-10 M, along with strong alkalis (NaOH or KOH), Ca rich additives and discrete fibers could enhance the stabilization performance with respect to strength, swell, and durability. Alkaline activation treatment is expensive compared to the conventional Portland cement based stabilization methods, and yet the cost can be significantly reduced by employing cost effective silicates for alkaline activation. Overall, the current state of geotechnical performance (compaction, strength, and durability) of stabilized expansive soil is satisfactory to adopt alkali activated binders (AAB) as a sustainable stabilizer to treat expansive soils, and however, as recommended in this review, further research should be advanced to realize the utmost viability of this promising approach in successful field application.
... Different researchers studied various methods of soil stabilization, for example, Tastan et al. (2011) observed that the addition of fly ash led to the increase in the soil strength, but the increment amount of soil strength depended on the soil type. Maaitah (2012) studied on geotechnical specifications of mixed lime with sodium silicate and observed that the curing time had a significant influence on the soil strength. Yilmaz et al. (2015) mixed Bayburt Stone with lime as an additive and used it KEYWORDS An environmental improvement method using albumen, which is convenient, cost-effective, rapid and environmentally friendly, has been used for soil stabilization. ...
An environmental improvement method using albumen, which is convenient, cost-effective, rapid and environmentally friendly, has been used for soil stabilization. In this research, the improvement influence of albumen added in various percentages to loess soil was investigated. Atterberg limits and compaction test were performed to study the influence of albumen on the soil. In addition, oedometer test and compression and extension triaxial tests were conducted to analyze geotechnical characteristics of the soil after treatment. From an engineering perspective, compression and extension strength of soils stabilized with 2% albumen at confining pressure of 200 kPa were 1.47 and 0.122 times larger than that of untreated soils, respectively. In all treated specimens, secant deformation modulus versus albumen content displayed higher values than untreated specimens, it means that deformability of treated specimens is less than untreated soil. In undrained compression test maximum pore water pressure decreased in treating specimens. Also, pore water pressure in extension triaxial test changed from negative to a positive value when treating the specimen with 2% albumen at confining pressure of 200 kPa. Treated specimens are shown more stable structure in comparison with untreated specimens. The behavior of the specimens changed to be more dilative, especially, in treating specimens with 2% albumen. Furthermore, settlement of the treated specimens decreased compared with untreated specimens. Field emission scanning electron microscopy images presented less porous and denser soil structure on the surface of treated specimens. Albumen additive can be implemented as a soil stabilizer in geotechnical projects.
... Chemical stabilization results in high pH values causing dissolution of silica and alumina in the clay particles. The dissolved particles react with the calcium provided by the hydraulic binder generating over the long-term pozzolanic reactions [11,12,13]. The latter cause reduction in water sensitivity, playing thereby an important role in the stabilization of soils. ...
The treatment of expansive soil is generally the most effective process for the stabilization of swelling clay. In this work, we will investigate the influence of the treatment of an expansive soil using granulated blast furnace slag (GGBS) alone and granulated blast furnace slag activated by cement (GGBS/C) by mechanical, physical and chemical tests. The results obtained show an increased pH, an improved plasticity as well as a significant reduction in swelling potential and swelling pressure following a percentage increase in additives. In addition, a change in the adsorption of methylene blue molecules (VBs) and in the microstructure of the expansive soil is observed after treatment. Utilization of both GGBS alone and GGBS activated by cement has a significant effect on the behavior of the swelling clay but the GGBS activated by cement exhibits superior results. The use of GGBS in the stabilization of soil will have both economic and environmental benefits.
... Woven and nonwoven geotextiles have been widely used in geotechnical applications such as foundations, retaining walls, slope stability, soil stabilization, and pavements [22]. Using expansive soil such as clayey soil in pavement construction induced hazardous problems due to volumetric changes with a change of saturation degree [23]. Non-woven geotextile (NWG) is selected in this paper due to its financial aspects and engineering properties such as reinforcement, cushion, separation, and drainage [24]. ...
This study investigated the potential effect of the non-woven geotextile reinforcing of the clayey sand treated with the copper slag (CS)-based geopolymer. To this end, preliminary tests such as standard compaction, P-wave velocity, pH, and Atterberg limits (Plasticity index) were conducted on variously treated samples. In addition, complementary tests including unconfined compressive strength (UCS), unconsolidated-undrained compression triaxial (UU), and scanning electron microscopy (SEM) analysis were performed on the reinforced samples. Furthermore, 0, 10, and 15% of CS and 0, 2, 4, 8, 12, and 16 M (M) NaOH concentrations were utilized in the investigation. The alkaline-activator solution (AAS) contained 70% of Na 2 SiO 3 and 30% of NaOH, and the weight ratio of CS-ASS was one. Subsequently, the selected samples were reinforced with 0, 1, 2, and 3 non-woven geotextile (NWG) layers by various arrangements. The results indicated the acceptable increase in the peak, residual strength, and failure axial strain. The UU results further demonstrated the improvement in shear parameters. The negligible and significant increases in the internal friction angle and the undrained cohesion were evaluated, respectively. The microstructural analysis elaborated the three mechanisms of geotextile, which helps to improve the mechanical behaviour of the reinforced samples. These mechanisms include contact, bending action, and interweaving action; interweaving action plays a vital role in the strength enhancement of samples.
... The alkalinity of the soil increases with an increase in Sodium Silicate, which helps in increasing the strength of the soil. When used with lime, it produces Calcium Silicate, which also increases strength and reduces swelling of soil (Maaitah, 2012). Due to the low solubility of Sodium Silicate and lime mixture, it is difficult to use them for in situ grouting. ...
Ground improvement will be critically important in the present and future geotechnical practice for designing the structures in weak soil. This paper presents a review of the recent development in ground improvement techniques, especially chemical stabilisers. Various available chemical stabilisers are identified and compared with other available methods. Though the use of chemicals provides an excellent alternative to the traditional methods, they still lack proper understanding regarding their use, handling, application, and long-term effect on the environment. Various chemical stabilisers and their applicability conditions are summarised in the present paper. Insight of biochemical, electrochemical, inorganic, and organic stabilisers is presented with future scope of these methods along with the potential areas where a lot of efforts is needed to industrialise these methods are also discussed briefly. A need for developing a more environmentally friendly and safe method was felt while reviewing these methods. Lack of a large amount of data is a major concern for lesser use of these methods industrially. A lot of laboratory and field experiments should be conducted in different conditions to ensure safe results from chemical stabilisers.
... The most conventional soil stabilizers are lime, Portland cement, fly ash, bottom ash, blast furnace slag, rice husk ash etc. However, the adverse environmental effect of cement discourage engineers to use it in ground improvement [7,8]. Rather, eco-friendly and low-cost available materials are much beneficial for the improvement works. ...
The rapid demand for urbanization expands the requirements of infrastructures and owing to the scarcity of available firm land; people are now built structures on soft soils. However, the application of a deep foundation for a low-rise structure may not be economically feasible for developing countries. The economic, as well as safe foundation, can be ensured by adopting traditional ground stability approaches. However, replacement of the industrial by-product, which possess minimum environmental threat may be a plausible option for ground stability. Therefore, an attempt is taken in this research to study the improvement of soft coastal soil by replacing with eco-friendly fly ash. The eastern bank of the river Karnaphuli, which has increasing industrial and residential demand is taken as a case study in this research. A series of experimental setups have been conducted to evaluate the strength development with different fly ash contents. It is found that the strength of fly ash treated soils increases with fly ash content up to a threshold value, and beyond that, the strength decreases. In addition, compaction and plasticity characteristics are also investigated through experimental observations and show better performance criteria with increasing fly ash contents. In a nutshell, this approach of replacing fly ash is suitable for coastal soil, and the experimental investigation reveals that an optimum 20% of fly ash content is justified.
... Some researchers (e.g., [40,68]) have attributed the highly alkaline nature of the pore fluid to the dissolution of Ca and OH ions as a result of mixing the soil with CaO in the presence of water. However, the decrease in pH of the pore fluid has been ascribed to: (1) the pozzolanic reactions that result in the depletion of soluble calcium concentration, especially at lime contents below the OLC of the soil [33,82], and (2) the removal of lime from the LLS samples under continuous leaching [60]. Similar trends in pH reduction under continuous curing and leaching have been reported by [34,61,83]. ...
Lime stabilisation is one of the traditional methods of improving the engineering properties of lateritic soils for use as subgrade and foundation materials for the construction of road pavements and highway embankments. Understanding the mechanical performance of lime-stabilised lateritic subgrades in terms of their durability under continuous water ingress will improve environmental sustainability by conserving scarce natural resources and reducing the environmental impacts of repair and replacement of pavements. However, there are several conflicting reports on the durability of lime-stabilised soils subjected to continuous water ingress and harsh environmental conditions. Therefore, this paper evaluates the influence of leaching on the physicochemical behaviour and durability of lime-stabilised lateritic soil under continuous water ingress, simulating the typical experience in a tropical environment. Variations in the strength and durability of the lateritic soil at various lime contents (0, 2.5, 5, 7.5, 10, 15, and 20 wt.%) and soaking periods (3, 7, 14 and 28 days) were evaluated by performing the California bearing ratio tests before and after subjecting the lime-lateritic soil (LLS) samples to continuous leaching using two modified leaching cells. Furthermore, physicochemical analysis was performed to assess the variation of cation concentrations and changes in the physical properties of the pore fluid as the leaching time progressed from 3 to 28 days. The results show that the minimum strength reduction index of the soil corresponds to its lime stabilisation optimum (LSO). Electrical conductivity decreased monotonically and almost uniformly with an increase in leaching time, irrespective of lime content. So, too, was calcium concentration and to a lesser degree for pH and potassium concentration. Adverse changes in the physicochemical behaviour of the LLS samples occurred at lime contents below and slightly above the optimum lime content of the soil. Whereas permanent pozzolanic reactions occurred at lime contents above the LSO and thus resulted in a 45-fold increase in strength and durability. The results are significant for reducing the detrimental effect of the leaching-induced deterioration of flexible pavements founded on tropical floodplains.
... Chemical additives are usually incorporated into soilcement mixtures to enhance the effectiveness of Portland cement as soil stabilizer by reducing the required quantity of cement. Also, it reduces shrinkage cracking and volumetric changes of stabilized soils, as well as increasing the durability and resistance of stabilized soils to adverse chemical compounds [20][21][22]. Some chemical additives can strongly modify the engineering properties of soils. ...
Chemical stabilisation using cement is a common method of improving the weak properties of soft soils. This study presents the results of experimental tests on the effects of three sodium additive solutions, sodium hydroxide (NaOH), sodium carbonate (Na2CO3) and sodium chloride (NaCl), on the strength of clayey (CS) and non-plastic/low plasticity property (NPS) soil-cement mixtures. Both soils condition, CS and NPS, represent the predominant soils in Mosul city, Iraq. The physical properties of these natural soils were obtained. X-ray diffractometry (XRD), X-ray fluorescence spectrometry (XRFS), and mercury intrusion porosimetry (MIP) tests were performed to further examine the microstructural characteristics of the soil samples. Furthermore, various concentrations of sodium additive solutions (0.5, 1, 1.5, 2, 2.5 and 3% by dry soil weight) were added to the soils to study the effect of these solutions on the unconfined compressive strength (UCS), California bearing ratio (CBR), and swelling potential characteristics of the soils. Variables such as cement content, curing period and concentration of chemical additives were considered. The results show an increase in the UCS of soil-cement mixtures corresponding to the incremental increases in the cement content and curing period of the samples. Also, the addition of NaOH and Na2CO3 increased the strength of soil-cement mixtures, with a limited effect in the case of NaCl addition. The results indicate that 1% and 1.5% of sodium additives were optimal additive contents for maximal UCS and CBR values, respectively. The results also confirm the decreased swelling potential of CS-cement mixtures with the addition of sodium additives and demonstrates the superiority of NaOH over Na2CO3 as an additive for soil stabilization.
... The appropriate type of additive is based on various factors, amongst which the chemical composition of the native soil and the environmental setting and the degree of improvement required can be highlighted [13,17,19,20,22,31,49,51,53]. Cement, lime and fly ash are some examples of admixtures used for modification of the volume change characteristics and shear strength behaviour of compacted fills [1,14,18,34,38,39,43,44,45,47,50,52]. One of the major drawbacks of the utilization of traditional additives is that, often a lengthy curing time is required and in some cases, relatively large quantities by volume are needed in order to achieve the desired improvement. ...
The volume change and uniaxial compressive strength of an alluvial soil stabilized with co-polymer of Butyl Acrylate and Styrene (CBAS) are presented in this paper. CBAS has low viscosity improving its adsorption into the soil microstructure and its ionic structure helps the formation of electrostatic bonding within the clay fabric. CBAS can be applied with ease by directly mixing or spraying onto soils, which potentially makes it favorable for use in compacted fills. Treatment of soil specimens with CBAS indicated significant improvement in the shrinkage and compressibility characteristics with just a percentage addition of 5% by dry mass of soil. On the other hand, obtaining an improvement in the swelling behaviour required at least a 10% addition of CBAS. The secondary compression rate and the uniaxial compressive strength are improved significantly even at very low percentages of treatment. Microstructural changes in the soil fabric are observed with the use of scanning electron microscopy, which indicated that CBAS-soil interaction can be achieved effectively by wet mixing.
... Chemical stabilization depends on chemical reactions between the soil particles and the stabilizer (cementitious materials) to attain a desirable impact Onyelowe and Duc 2018). During the last few decades, various mitigation techniques have been adopted to control the potentially deleterious effects of expansive clays on infrastructures including clay soil replacement, adjustment of water content and compaction, addition of fibrous materials (Abdi and Mirzaeifar 2016;Soltani, Deng, and Taheri 2018), stabilization via chemical substances (Maaitah 2012;Correia, Venda Oliveira, and Lemos 2018) and long-established chemical remediation by means of lime, cement and fly ash addition (Kampala et al. 2013;Jahandari et al. 2019). ...
Lime is commonly used for treatment of clays. Factors influencing the stabilization process include clay mineral and content, type of lime, etc. Current paper presents results of examining the effects of miscellaneous plasticity on the behavior of lime stabilized kaolinites. Kaolinites with plasticity indices of 10, 19 and 26% were treated with 1, 3 and 5% lime and cured for 1, 7 and 28 days. Effects of lime on compaction, compressive and shear strength parameters of mixtures were examined. Lime addition had the least influence on compaction characteristics of the kaolinite with plasticity index of 10% as compared with those having plasticity indices of 19 and 26%. Greatest and lowest improvements in compressive strengths, moduli of elasticity and shear strengths were respectively achieved by kaolinite with plasticity indices of 10 and 26%. Curing period showed a very influential factor on lime stabilization process and the changes observed.
... Among all methods used in practice, it is common to utilize shallow mixing with a stabilizing agent (pozzolanic or chemical admixture) followed by compaction. The intent is to improve the interactions within the clay fabric and the interactions of these with other ions present in the medium such that permeability, shear strength, and overall durability of the compacted clay are improved (Lahalih and Ahmed, 1998;Inyang et al., 2007;Yazdandoust and Yasrobi, 2010;Maaitah, 2012;Soltani, 2016;and Tajdini et al., 2017). Based on the properties of a particular clay and the surrounding environmental conditions, various stabilization agents might be considered. ...
The internal stability of alluvial clays may be significantly compromised during a heavy rainfall due to infiltration of surface water causing sudden inundation, softening, and loss of erosion resistance or mechanical strength. Most of the available stabilization methods for clay soils employ pozzolanic or other cementitious binders, creating a chemically bound clay-admixture matrix. These admixtures commonly require a curing period after placement and compaction. Alternatively, aqueous polymers can be used in diluted form without any need for a curing period. Aqueous polymers can form agglomerations of clay particles enclosed in a matrix of polymer chains, held together by electrostatic and hydrogen bonding, improving erosion resistance. In this research, an aqueous polymer, namely, copolymer of butyl acrylate and styrene (CBAS), is mixed with alluvial clay sampled from Famagusta Bay, Cyprus, and the clay stability test is performed as a basis for assessing the degree of improvement on erosion resistance. A time-dependent approach for the evaluation of test results is followed to increase the accuracy of the analysis of the actual behavior observed during the test. A significant improvement in the erosion resistance is observed in treated test specimens. The mode of collapse of specimens during the clay soil stability test when aqueous polymer is used also changed from being gradual cracking and slaking to explosive. The swelling behavior and the effect of drying on the erosion resistance are also observed in the testing program. X-ray diffraction analysis and Fourier transform infrared spectroscopy are performed for observation of the effect of CBAS on microstructural interactions, such as electrostatic bonding and changes in soil fabric.
... Thus, it becomes necessary to introduce artificial stabilization measures to make sure these dumps remain stable for a safer mining operation and simultaneously hold large volumes of overburden material. Among the many methods of dump stabilization such as mechanical stabilization [15,16,17,18,19], chemical stabilization [20,21,22,23], and biological stabilization[24, 25, 26]. One of the latest method is to stabilize the dump slopes using fly ash composite layers. ...
... However, the UCSs of all soil-hexametaphosphate mixtures were lower than that of the pure soil. Maaitah (2012) investigated clay stabilization used for sub-base with lime and sodium silicate. The shear strength of the clay mixture was the highest when 5% of lime and 2% of sodium silicate were properly mixed. ...
Unconfined compressive strength (UCS) of high plasticity clayey soil mixed with 5 and 10 % of Portland cement
and four chemical agents such as sodium hexametaphosphate, aluminum sulfate, sodium carbonate, and sodium silicate with 0,
5, 10, and 20% concentrations was comparatively evaluated. The individual and combined effects of the cement and chemical
agents on the UCS of the soil mixture were investigated. The strength of the soil-cement mixture generally increases with
increasing the cement content. However, if the chemical agent is added to the mixture, the strength of the cement-chemical
agent-soil mixture tends to vary depending on the type and the amount of the chemical agent. At low concentrations of 5% of
aluminum sulfate and 5% and 10% of sodium carbonate, the average UCS of the cement-chemical agent-soil mixture slightly
increased compared to pure clay due to increasing the flocculation of the clay in the mixture. However, at high concentrations
(20%) of all chemical agents, the UCS significantly decreased compared to the pure clay and clay-cement mixtures. In the case
of high cement content, the rate of UCS reduction is the highest among all cement-chemical agent-soil mixtures, which is more
than three times higher in comparison to the soil-chemical agent mixtures without cement. Therefore, in the mixture with high
cement (> 10%), the reduction of the USC is very sensitive when the chemical agent is added.
... The balanced out test with (4 and 6%) lime turns out to be more solid against the WD cycles. [17] 4. MATERIALS Following are the materials which are to be used in this study. ...
The thriving urban population of India advances development of growth of trade, commerce, service sector which depend on heavy commercial vehicles and individual ascent in income contributing to rise in motorization andexperiencing quick accelerations in urban travel interest putting weight on restricting street space surpassing the heap conveying limit of roads in the steadily changing atmosphere of our nation particularly on road running in clayey soil ranges are known for bed condition and unpredictable conduct of the nature of the soil contributing to failure of roads thereby compelling rise in maintenance cost. It is the responsibility of the road authorities to use the local materialand correct the soil properties using additives enhancing the strength of soil and make the road durable. The examination was completed to focus first soil engineering properties (with and without stabilizer), standard compaction; four days soaked California Bearing Ratio (CBR), permeability test and cyclic loading test according to codal procurement. A concoction named Terrasil was utilized as stabilizer and it was utilized for altered measurement i.e. 0.041% by dry aggregate weight of soil test according to the convention of Zydex Industries, Vadodara. Test outcome demonstrates that designing properties got modified and CBR on stabilized clayey samples increased considerably, which reflects the lower thickness in correlation with natural characteristic soil properties.Additionally the expense is diminishing which advantages the road builders, engineers, policy makers and pavement designers as well.
... They showed that adding 5% rice husk fly ash and 4% lime is most effective in increasing the compressive strength of the soil. Maaitah (2012) showed that the strength of soil mixed with 4% hydrated lime and 2% sodium silicate was increased significantly. Tempest and Pando (2013) tested the effects of SSA on a clay soil. ...
Using various additives has been considered as one of the most common stabilization methods for improvement of engineering properties of fine-grained soils. In this research the effect of sewage sludge ash (SSA) and hydrated lime (HL) on compressive strength of clayey soil was investigated. For this purpose, 16 kinds of mixtures or treatments were made by adding different amounts of SSA; 0, 5, 10 and 15% by weight and HL; 0, 1, 3 and 5% by weight of a clayey soil. First, compaction characteristics of the treatments were determined using Harvard compaction test apparatus. So that, 12 unconfined compressive strength test specimens were made using Harvard compaction mold from each treatments taking into account four different curing ages, including 7, 14, 28 and 90 days in three replications. Therefore, a total of 192 specimens were prepared and subjected to unconfined compressive strength tests. The results of this study showed that the maximum dry density of the treated soil samples decreases and their optimum water content increases by increasing the amount of SSA and hydrated lime in the mixtures. It is also found that the adding of HL and SSA individually would increase the compressive strength up to 3.8 and 1.5 times respectively. The application of HL and SSA with together could increases the compressive strength of a clayey soil more efficiently even up to 5 times.
... Previous studies [11][12][13] have indicated that cement is often used as a main additive of binders for the enhancement of the soil strength and stiffness through curing time. When the cement is used for soil treatment, the reaction between the cement with soils and water produces a hardened material known as cemented soil. ...
In recent years, the deep mixing technique that utilizes cement-based grout mixtures has become a popular approach, particularly for the enhancement of soft soils. Despite the advantages of deep mixing technique in numerous construction applications, the effort given for this technique still needs to be extended using new material as additive. Thus, this study investigates the use of cement-based grout combined with glass powder to enhance the clay soil via deep mixing technique. An experimental program has been conducted including grout mixtures at different replacements of glass powder (0%, 3%, 6% and 9% by dry weight of binder) mixed with clay having different water contents (36%, 31% and 21%). The Vicat, unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests have been carried for analysing performances of mixtures. The results indicate that the setting times of the mixture pastes increase, while the bulk densities of the soilcrete samples do not significantly change with the replacement of glass powder. Moreover, due to the use of glass powder, both the UCS and UPV increase alongside decreasing water content as well as increasing curing time. Test results imply that, owing to the replacement of glass powder, all UCS values of the soilcrete samples are applicable for the purpose of deep mixing. However, the replacement of glass powder by 3% produces a more favorable UCS response. Strong correlations exist for the UCS versus elastic modulus (R ⩾ 0.84) as well as for the UCS versus UPV (R ⩾ 0.82), which practically could be useful for the strength predictions of soil-cement columns. Consequently, the use of cement-based grout with the glass powder replacement could provide a new insight into the deep mixing technique for the treatment of clay. Moreover, the employment of glass powder as a waste material could also benefit the environment and construction costs.
... Testing to determine the Atterberg limits and swelling was carried out on all samples according to ASTM D4318, 2010 and ASTM D4546, 2008 standards, respectively. Samples preparation for swelling test similar to previous researches (Al-Rawas et al., 2005;Maaitah, 2012;Aldaood et al., 2014a;Aldaood et al., 2014b;Zha et al., 2008;Al-Mukhtar et al., 2012;Cokca et al., 2009;Abu Seif, 2015;Urena et al., 2013;Kilic et al., 2015) was conducted. Initially optimum moisture content (%ω opt ) and maximum dry density (γ d ) based on compaction test ...
Lime and fly ash are admixtures used to reduce the swelling of clay. The current study added 3%, 5%, and 7% (wt) of lime to sulfate-bearing clay and found that chemical reactions between the lime and sulfate-bearing clay led to ettringite formation as the lime content increased. This mineral shows good potential for water absorption, which increased the swelling percentage and pressure and the plastic properties of the clay. It was shown that lime is incapable of improving the swelling properties of sulfate-bearing clays. Next, 3%, 5%, and 7% (wt) of fly ash was added to the clay. Fly ash suppressed swelling and decreased the plasticity index of the clay. The optimum content of 3% (wt) fly ash improved the swelling properties of the sulfate-bearing clay. The fly ash was then added to 5% lime-stabilized sulfate-bearing clay. The results showed that the fly ash compensated for the negative effects of the lime, reducing the swelling percentage and pressure and the plasticity index of the lime-stabilized sulfate-bearing clay.
... Based on this, ICL for the soil was determined as 5.5 %. ICL values as low as 2 % [11,54] and in some cases even up to 8 % [10] for organic soils have been reported. The OLC determined from UCC tests amounted to 7 %. ...
The use of phosphogypsum as an additive to lime, to enhance its performance in soil stabilization, is analyzed in this paper. Phosphogypsum is a by-product of the phosphate rock processing during production of phosphoric acid. Expansive soil samples used in this paper were stabilized using three different lime proportions: initial lime consumption, optimum lime content, and less than initial lime consumption. The results reveal that the addition of phosphogypsum to lime led to improvement of both the early and late strength of stabiliszd soil.
... Muntohar (2011) pointed out that the compressive and flexural strengths of clay bricks were enhanced by adding a lime-RHA mixture, and the best proportion was achieved at a ratio of 1∶1 of lime and RHA. Maaitah (2012) reported that the physical properties of treated soil were enhanced by mixing lime and sodium silicate. Mir and Sridharan (2013) worked on effect of high-calcium and low-calcium fly ashes on highly expansive soil. ...
Alternative sulfur management solutions are of great interest to scientists and engineers due to the increase in the world's sulfur product. Although use of by-product sulfur as a binder in concrete has been addressed in previous reports, almost no work has been done to investigate the potential use of by-product sulfur as stabilizer agent for soil. This paper presents the geotechnical characteristics of sandy soil form the southern Caspian Sea Coastal Area of Mazandaran State, Iran, stabilized with modified sulfur. Specimens cured up to 180 days and unconfined compression and direct shear tests were performed. Unconfined compression strength and direct shear parameters increased, depending on modified sulfur content and curing period. Empirical relationships are proposed to estimate the unconfined compressive strength and direct shear parameters. Our results showed that a modified sulfur agent has considerable influence on the physical characteristics of soil. Sulfur may be employed as soil stabilizer in civil engineering construction fields. (C) 2014 American Society of Civil Engineers.
Periodic wet–dry processes are a significant weathering mechanism that can quickly alter a soil’s mechanical characteristics, reducing its resilience and durability. This study investigates the physical and microstructural characterization of stabilized soils through experimental analysis. While the conventional approach to ground improvement involves the application of ordinary Portland cement (OPC) and lime for treating unstable soil, this research explores calcium sulfoaluminate (CSA) cement as an eco-friendly alternative with comparable efficacy and fewer adverse environmental effects. The primary objective is to evaluate the impact of cyclic wet–dry (W–D) events on the durability and stability of CSA cement-treated sand using comprehensive laboratory testing. Various samples were prepared with cement contents of 3%, 5%, 7%, and 10%, corresponding to the optimum moisture content. Stabilized soil specimens underwent testing for unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) after curing for 3, 7, 14, and 28 days. Subsequently, these specimens were exposed to zero, one, three, five, and seven W–D cycles. The outcomes show a decrease in the strength and durability index of the soil with a rising number of W–D cycles. However, the decline in the strength and durability of CSA-treated soil samples is significantly mitigated as the CSA content increases from 3% to 10%. The findings indicate that after seven W–D cycles, the UCS value of 10% cemented samples dropped by 14% after 28 days of curing, whereas 3% specimens experienced a 28% loss in strength. Similarly, UCS values for 5% and 7% cement content reduced from 666 kPa to 509 kPa and from 1587 kPa to 1331 kPa, respectively, indicating improved resilience with higher CSA content. The durability index was less affected during the first three cycles, but showed a more pronounced decline after five and seven cycles. For 3% cemented soil, the durability index dropped from 0.95 to 0.71, whereas for 10% cemented soil, it decreased from 0.97 to 0.82 after seven W–D cycles. The scanning electron microscope (SEM) also determines the cement–soil interaction before and after W–D, and it was noted that the pores and cracks increased after each cycle. Based on the findings, it is established that subgrade materials treated with CSA cement demonstrate durability, environmental sustainability, and suitability for integration into road construction projects.
The phenomenon of swelling of clay soils is the cause of deformation of these soils and damage to the structure. Given the complexity and importance of this phenomenon, several experimental methods have been proposed for its characterization. However, in addition to these experimental methods, which are often time-consuming and costly, they can also yield very different results.The main objective of this work is to propose predictive approaches to the potential and swelling pressure of clay soils, using easily obtained elementary soil properties.To this end, numerous data sources have been collected from research projects published in the literature in previous years.The combined use of several elementary soil properties such as the liquidity limit and plasticity index (LL and IP), water content (w)and clay fraction(FC) as explanatory variables, has allowed us to develop models for predicting swelling potential and pressure that have provided acceptable statistical indicators characterized by high coefficients of determination (R 2).The models developed were validated with satisfactory efficiency. Statistical tests of Fisher (F-test) and Student (t-test) were conducted and showed that these models and their parameters are globally significant.In addition, the comparison between predicted values and experimental data and the parametric studies carried out have 2 shown that the proposed models can reasonably be used as reliable tools to predict the potential and swelling pressure of clays using elementary soil properties.
Lignin is a natural copolymer found in plants that is a major waste from bioenergy and paper industries. In this study, comprehensive laboratory testing programs were carried out to evaluate the strength improvements and water resistance of soil after being stabilized by lignin and polymerized lignin. The chemical polymerization of pre-treated lignin involves a process of linking short lignin molecules to form longer ones and consuming hydrophilic functional groups to improve its stability under wet conditions. Various testing combinations were considered, including four lignin or polymerized lignin contents (0, 6, 8, and 10 %) and four lime contents (0, 2, 4, and 6 %). The results show that lignin-stabilized soil will take at least 14 days to reach maximum strength, whereas the minimum curing period is 21 days for soil stabilized with polymerized lignin. The optimum dosage is 8 % when lignin or polymerized lignin is used for soil stabilization. Polymerized lignin can provide approximately 10 to 20 % more strength improvement than lignin; however, lime seems work better with lignin than polymerized lignin when added as a strength booster. The water soaking tests showed that polymerized lignin has better moisture resistance than lignin, and additional lime can further improve the performance of stabilized soil with respect to water susceptibility. However, the strength of specimens cannot fully recover, decreasing slightly after each dry–wet cycle for both specimens treated by lignin and polymerized lignin. The total decrease is about 5∼10 % after two cycles. The temperature and pH value control and oxygen supply approach used in this study will be an important reference for future studies.
The phenomenon of shrinkage-swelling in clayey soils can cause soil deformation and damage to buildings. Existing experimental methods for characterizing this phenomenon are complex, time-consuming, and yield distinct results. This study aims to propose a new formula for estimating the swelling pressure of clayey soils using basic soil properties. Data from various research projects published between 1988 and 2019 were collected to develop a prediction model. The model utilizes elementary soil properties such as liquid limit (LL), plasticity index (PI)and clay fraction (CF) as explanatory variables. The statistical indicators of the model, including the coefficient of determination (R2), were found to be acceptable. The empirical model was successfully validated and deemed globally significant based on Fisher (F-test) and Student (t-test) statistical tests. Comparisons between predicted swelling pressure values and experimental data, along with parametric studies, demonstrated the reliability of the proposed model as a tool for predicting the swelling pressure of clays using elementary soil properties.
The study investigates the use of spent coffee (SC), a post-consumer coffee waste, as a stabilizing material in combination with cement (C) for soil improvement. The study explores the influence of different maximum particle sizes of silty sand soil on the resistance behavior when stabilized with cement and various proportions of spent coffee. The substitution ratios used were 0%, 3%, 6%, 9%, and 12% of spent coffee in place of cement. Each replacement ratio was mixed with soils and cement at three different maximum soil sizes (0.6 mm, 2 mm, and 4.25 mm), with an optimum water content and a binder (SC+C) to soil ratio of 0.2. After curing for 14 and 28 days, the unconfined compressive strength (UCS) of the treated soil was tested. The results indicated that samples with up to 6% SC replacement maintained their strength or exhibited slight decreases throughout the curing period. However, at higher replacement ratio, the strength decreased. Additionally, increasing the maximum size of soil particles led to improved strength properties.
Soil stabilization using additives is considered as one of the sustainable alternative techniques to deal with acute material shortages. Critically reviewing the contemporary works on soil stabilization would help practitioners and researchers to comprehend the merits and demerits of each stabilization method, influential parameters, and associated constraints. Furthermore, the critical analysis might aid the authorities to develop standard protocols about the use of various additives for soil stabilization, which would persuade the industry personnel to adopt sustainable practices. This paper presents a methodical review of the present soil stabilization methods under five key areas namely, underlying chemistry, the influential factors, performance indicators, economic and environmental aspects, and industrial perspectives. Findings of the review indicate that cement-based stabilizers perform well irrespective of soil type and curing conditions, on the contrary, lime-based stabilizers require appropriate temperature and pH for strength development. The degree of stabilization depends mainly on soil type, compaction level, and curing type and condition. Most of the soils treated with different additives exhibited a reduction in plasticity index, and maximum dry density against stabilizer dosage irrespective of soil type. The typical values of unconfined compressive strength and California bearing ratio of inorganic and organic soils except for peat, treated with a 5% dosage of all common types of stabilizers, fall in between 700-1,500 kPa and 30-60%, respectively. Cement and cementitious blends exhibited better cost-to-strength, energy-to-strength, and CO2 emission-to-strength ratios for soils with low plasticity whereas lime-blended stabilizers seemed effective for high-plastic soils.
Encryption is the technique used to convert a plain text message into cipher text which is unreadable to human or machine. Encryption is of two types, namely: symmetric key
encryption and asymmetric key encryption. Encryption scheme in which both the sender and receiver share the same key is referred to as symmetric key encryption scheme. Encryption scheme in which encryption and decryption are performed using different keys, i.e. a public key and a private key is referred to as asymmetric key encryption scheme.
This paper presents a performance comparison between four popular and commonly used encryption algorithms: Data Encryption Standard (DES), Triple Data Encryption Standard (3DES), Advanced Encryption Standard (AES) and Rivest-Shamir-Adleman (RSA). DES, 3DES, and AES are symmetric key encryption algorithms while RSA is an asymmetric key encryption algorithm. The comparative analysis is carried out based on their Architecture, Scalability, Flexibility, Reliability, Security and Limitation that are ssential for secured communication (Wired or Wireless). The results achieved form a baseline in choosing an encryption algorithm that is more efficient and that have strength against cryptanalysis.
This study explores the possibility of using alkali lignin as a soil stabilizer as well as the possibility of polymerizing alkali lignin to further improve its performance. The polymerization involves cross-linking phenoxy radicals of lignin precursors to form longer molecular chains in the presence of laccase as a catalyst. In this study, soil was treated with different lignin contents (8%, 10%, and 12%) under different water/lignin ratios (0.4, 0.6, 0.8, and 1.0) and then cured in air or heat for various durations (4, 7, 14, and 21 days). Specimens treated by lignin and polymerized lignin were tested to determine the unconfined compression strength (UCS). For the specimens treated by lignin, the results showed that a higher lignin content can improve the UCS if the specimens were cured in the air, and heat curing can improve the strength by more than 40% compared with the ones cured in the air. The tests indicated that excessive lignin content would cause bleeding that prevented further increase of the strength. Moisture was identified as a main factor causing loss of strength of the treated specimens. Polymerization appears to be an effective approach to further improve the strength. Polymerization decreased the hydrophilicity and increased the length of molecular chains, which greatly enhanced the strength of treated soil. According to the results, a combination of polymerization and heat curing would provide the highest strength, which was approximately 10 times higher than the ones treated with regular lignin and cured in air.
Unconfined compressive strength (UCS) of high plasticity clayey soil
mixed with various amounts of cement and four dispersive agents was evaluated to
investigate the effectiveness of the agents combined with the cement on the
stabilization of the soil. A series of unconfined compression tests was conducted for
the clay specimen mixed with 5 and 10 % of cement and four chemical agents such as
sodium hexametaphosphate, aluminum sulfate, sodium carbonate, and sodium silicate
with 0, 5, 10, and 20% of concentrations. The strength of the cement-soil mixture tends
to mostly decrease when the mixture includes the agent. However, at low
concentrations of aluminum sulfate (5%) and sodium carbonate (5% and 10%), the
average UCS the soil-chemical agent-cement mixtures slightly increased compared to
that of pure clay due to increasing the flocculation of the clay in the mixture. At high
concentrations (20%) of all chemical agents, the UCS decreased considerably. With
increase in cement content from 0 to 10% in the mixture, the degree of the UCS
reduction remarkably increased. For 10% of cement, the UCS reduction is the highest
for all soil mixtures containing chemical agent-cement, which is more than three times
higher compared to that for the soil mixtures without cement.
This paper examines the efficiency of 75 mm diameter lime piles in altering the physico-chemical and engineering properties of a compacted expansive soil. Calcium and hydroxyl ions from the lime pile migrated into the surrounding soil mass and increased the soil pH and pore salinity. The increase in soil pH from lime migration could not increase the soil pH to levels (⩾ 12) that were conducive for pozzolanic reactions. The increase in soil pH, however, increased the exchangeable calcium ion content of the soil by apparently imparting additional negative charge to the clay particle edges. Lime modification reactions due to increased pore salinity and exchangeable calcium ions suppressed the plasticity index and swell potential, and slightly increased the unconfined compressive strength of the compacted expansive soil.
Dans cet exposé, nous examinons la capacité des piles de chaux de 75 mm de diamètre ont de à changer les propriétés physico-chimiques et industrielles d'un sol expansif compacté. Les ions de calcium et d'hydroxyle présents dans la pile de chaux migrant dans la masse du sol avoisinant environnant, augmentant son pH et la salinité des pores. L'augmentation du pH du sol causée par la migration de chaux ne peut atteindre des niveauzx (⩾ 12) qui favorisent favorisant des réactions pouzzolani-ques. Cependant, l'augmentation du pH du sol augmente la teneur de celui-ci en ions de calcium échangeables en apportant apparemment une charge négative supplémentaire sur les bords des particules d'argile. Les réactions de modification de la chaux dues à une plus grande salinité de pores et aux ions de calcium échangeables suppriment l'indice de plasticité et le potential de gonflement et augmentent légèrement la résistance à la compression non confinée du sol expansif compact.
The impact of the variation in compaction condition on the swelling and shrinkage behavior of three soils has been examined.
Two natural soils, namely red soil and black cotton soil, and one artificially mixed soil sample of commercial bentonite with
well-graded sand, were studied. Compaction curve for Standard Proctor conditions were plotted and four compaction conditions
were selected. Experimental results showed that clay mineralogy dominates over compaction conditions in influencing the swelling
and shrinkage behavior of the tested soils. Monitoring of void ratio (e)−water content (w) relations during shrinkage showed
that soil specimens generally shrunk in three distinct linear stages. A small reduction in void ratio occurred on reduction
in water content during the first shrinkage stage and was termed as initial shrinkage. In second stage, void ratio decreased
rapidly with reduction in water content and was termed as primary shrinkage. In third and final stage, reduction in water
content is accompanied by a marginal change in void ratio and it’s called residual shrinkage. Irrespective of initial compaction
conditions studied, the transition from primary to residual shrinkage for all the specimens occurred within a narrow range
of water content (10–15%).
Generally the amount of lime needed to modify a clay soil varies from 1 to 3 percent, whilst that required for cementation varies from 2 to 8 percent. Montmorillonitic clay soils respond more rapidly to lime treatment than do those in which kaolinite is the dominant clay mineral. When lime is added to clay soils, calcium ions are combined initially with or adsorbed by clay minerals which leads to an improvement in soil workability. Lime added in excess of the fixation point is utilized in the cementation process and gives rise to an increase in soil strength. The principle uses of the addition of lime to clay soils is for, firstly, stabilization of subbases and subgrades in pavement construction and, secondly, to dry out wet soils. Lime treatment also has been used to stabilize embankments and canal linings, and to improve foundation soils. In the latter instance soil is stabilized beneath strip or raft foundations, or lime piles or columns are formed.
Marine clays are present in many parts of the world and these deposits are characterized by poor engineering properties such as low strength and high compressibility. These deposits are sensitive to changes in the stress system and the system chemistry of the pore fluid, and the use of a lime stabilization technique for such problematic clays is not new. In the present investigation an attempt was made to examine the diffusion of lime in the lime treated marine clay from the lime column or lime injection points and the changes which occurred in the engineering behavior of the soil system. The formation of new reaction products due to soil-lime reactions has resulted in particle growth of soil particles and the same has been confirmed using scanning electron microscopy. The test results indicated that the presence of excessive sodium ions in sea water do not retard the effective penetration of lime into the soil and that there is significant improvement in the engineering behavior of the soil system. The lime column and lime injection techniques can therefore be conveniently used to improve the behavior of soft marine clay deposits.
Lime modification has the potential to reduce greatly the delays to construction projects caused by wet weather. The initial consumption of lime (ICL) test, currently used as an indicator of how much lime to use, is shown to produce results that can be both inconsistent and excessively conservative. Interpretation based on the full pH against lime addition curve is suggested. Changes in plasticity with both time after mixing and lime content are examined for four British clays, comprehensive Atterberg limit testing being shown to be adequate for design. The points at which full modification occurs are interpreted from these changes and complement well those determined by the modified ICL test. Changes in plasticity caused by smaller lime additions are shown to be adequate in many cases to improve site workability.
In unsaturated soil modelling, collapse is viewed as an ordinary response, whereas swelling upon an increase of moisture is
considered as a special class of problems. However, an investigation based on fundamentals of plasticity indicates that the
two seemingly opposite responses are unified within the same ordinary elastoplasticity framework. In fact, similar to the
well-known contractive and dilative responses in the critical state framework, the collapsive and expansive responses of unsaturated
soils differ only in the sign of the dissipative hydrostatic stress. For a soil with a low applied net stress, the dissipative
mean normal stress during wetting is likely to be negative, and the plastic volumetric strain is kept negative (swelling)
as well, such that the dissipation is always positive, complying with the second law of thermodynamics. When the applied net
stress is high, the dissipative mean normal stress may turn to be positive, resulting in a positive plastic volumetric strain
(collapse). This paper explains the concept of this ‘ordinary’ modelling framework, and uses a bounding surface triaxial model
to demonstrate the concept. The numerical results are compared with experimental observations reported in the literature.
KeywordsConsolidation–Constitutive relations–Expansive soils–Plasticity–Suction–Unsaturated soil
Clay soil can be stabilized by the addition of small percentages, by weight, of lime, thereby enhancing many of the engineering properties of the soil and producing an improved construction material. In order to illustrate such improvements, three of the most frequently occurring minerals in clay deposits, namely, kaolinite, montmorillonite and quartz were subjected to a series of tests. As lime stabilization is most often used in relation to road construction, the tests were chosen with this in mind. Till and laminated clay were treated in similar fashion. With the addition of lime, the plasticity of montmorillonite was reduced whilst that of kaolinite and quartz was increased somewhat. However, the addition of lime to the till had little influence on its plasticity but a significant reduction occurred in that of the laminated clay. All materials experienced an increase in their optimum moisture content and a decrease in their maximum dry density, as well as enhanced California bearing ratio, on addition of lime. Some notable increases in strength and Young's Modulus occurred in these materials when they were treated with lime. Length of time curing and temperature at which curing took place had an important influence on the amount of strength developed.
This book provides a summary of the state-of-the-art of expansive soils and practical solutions based upon the author's experience. Part I discusses theory and practice, and summarizes some of the theoretical physical properties of expansive soils. It also discusses various techniques employed to found structures on expansive soils such as drilled pier foundation, mat foundation, moisture control, soil replacement, and chemical stabilization. Part II presents case studies. The author has found that few records are available on the cause of structural distress, their remedial measures, and more important, the degree of success after those measures have been completed.
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